Scale: Unknown. A model of an annular cylinder engine made in metal and wood and patinated in parts. The engine is depicted mounted to the floor of a stylised wooden section of hull made in polished mahogany. The engine has two large cylinders, the tops of which are lacquered brass and the pistons can be turned over by rotating a large wheel at one end. The cylinder bodies, engine housing, wheel, and other components are gun metal plated brass. The crank shaft is visible at the opposite end to the wheel and is attached to two short levers. The steam inlet pipes are copper plated and are depicted in broken form. The model is mounted on four gun metal plated pillar supports, fixed to a mahogany baseboard with bevelled edges. On plaque inscribed "Maudslay Sons and Field annular cylinder engine for screw propulsion Joseph Maudslay patentee August 1856". On paper label applied to baseboard: "2".